Justin Hwang

US Patent:

7728676, Jun 1, 2010

Filed:

Apr 30, 2008

Appl. No.:

12/112914

Inventors:

Lalitkumar Nathawad - Costa Mesa CA, US
Justin Hwang - Mountain View CA, US

Assignee:

Atheros Communications, Inc. - Santa Clara CA

International Classification:

H03L 7/00

US Classification:

331 16, 331 17, 331167, 331117 R, 331177 R

Abstract:

A voltage-controlled oscillator (VCO) comprising a first circuit, a second circuit, a comparator circuit, and a control unit. The first circuit can determine an output common mode voltage associated with an output of the VCO. The second circuit can generate an upper control voltage limit and a lower control voltage limit associated with a control voltage received by the VCO based, at least in part, on the output common mode voltage. The comparator circuit can compare the control voltage to the upper and lower control voltage limits. The control unit can determine whether to change a switched capacitance associated with the VCO based, at least in part, on whether the control voltage is outside the upper and lower control voltage limits, thereby maintaining an optimal region of operation for the control voltage.